There are known surgical treatment devices using microwaves so as to perform coagulation, hemostasis, incision, and the like with respect to body parts such as digestive organs, the liver, the bladder, the prostate, the uterus, blood vessels, and the intestinal canal.
Specifically, a conventional electrosurgical knife or the like uses Joule heat generated by using a high-frequency voltage at a frequency of approximately 500 kHz so as to heat and coagulate a surface of a living tissue. When the coagulation is performed with such a conventional electrosurgical knife or the like using Joule heat, a living tissue is easily coagulated, and hence the coagulated surface may be peeled off and dropped from the living tissue.
Meanwhile, when a microwave is applied to a living tissue between electrodes, dielectric heat is generated in the living tissue by a near electromagnetic field formed by microwave power. The dielectric heat evaporates moisture of the living tissue, and the living tissue is coagulated and fixed. In this way, a vascular vessel is sealed, and a hemostatic effect is achieved.
When coagulation and hemostasis are performed by using microwaves, the living tissue can be coagulated at a relatively low temperature. Thus, the living tissue can be kept in a fixed state in which a function of the living tissue is stopped while maintaining a cell shape of the living tissue. Thus, a situation that the coagulated surface is peeled off or dropped from the living tissue is prevented.
Japanese Patent Application No. JP 2005-21658 A and Japanese Patent Application No. JP 2007-282666 A each disclose a device which uses microwaves as described above so as to perform coagulation, hemostasis, incision, and the like with respect to a living tissue. Treatment using microwaves involves a problem of a spark that may be generated by electrodes brought into contact with each other. The spark causes excessive damage to a living tissue. As a countermeasure, the medical treatment device disclosed in Japanese Patent Application No. JP 2007-282666 A is designed to prevent generation of the spark by preventing two electrodes from being brought into contact with each other at the time of holding a living tissue so as to maintain a parallel state therebetween. However, in the medical treatment device disclosed in Japanese Patent Application No. JP 2007-282666 A, a turning shaft of an electrode and a point of effort (position at which electrode open/close rod is mounted) exist in the same electrode, and a distance therebetween is small. Thus, the electrode cannot be lightly turned, and hence delicate work during a surgical operation is not easy. Further, a lower blade electrode connected to a central electrode is close to a conductive holder connected to an external conductor, and a distance from a distal end portion of coaxial cables to blades for cutting off a living tissue is long. Thus, there is a problem that a microwave is not efficiently applied to a living tissue.